A tamper evident container closure can be applied to a container body but cannot be removed without leaving evidence that the package has been tampered with.
Re-closable packages are used for a variety of goods that are stored in the home and to which it is undesirable for children to have access. These can include risky items such as pharmaceuticals or cleaning products or high-value products such as baby milk powder. Typically childproof containers use mechanical means which require greater intelligence or dexterity to operate. These can also confound the intended users. Moreover, a child attempting to open a re-closable package will not necessarily attack the lid but may simply try to prise the whole closure from the container, bypassing sophisticated childproof locking mechanisms.
Those with malicious intent may wish to contaminate the contents of a filled and un-opened container. Counterfeiting by the refilling of genuine containers also represents a serious risk to consumers and brand owners. While it is desirable that closures should be readily applied to the container body during the manufacturing process and also be separable for recycling and waste disposal purposes, the prevention of counterfeiting and contamination requires either that the separation be evident or result in such destruction of the closure and/or container body that it cannot be re-used.
The present invention particularly relates to large containers such as used for baby milk powder as described in WO 2011/067585 A (BAPCO CLOSURES RESEARCH LTD) Sep. 6, 2011. This type of container uses a closure having a spout that fits to a container body and defines an opening and a lid which closes over the spout. The amount of foil required to seal across the whole opening is necessarily large and adds considerably to the expense of such closures.
The use of the BAP (Registered Trademark) technology as described in WO 99/61337 A (SPRECKELSEN MCGEOUGH LTD) Feb. 12, 1999 whereby an induction heat sealed foil is bonded to both the container body and the closure and is removable by tearing out rather than peeling away, provides some intrinsic tamper evidence.
Existing BAP (Registered Trademark) closures typically use either a full foil across the whole of a mouth of the container or an annular (donut) foil in a slot around the periphery of the spout such as described in WO 2006/010960 A (BAPCO CLOSURES RESEARCH LTD) Feb. 2, 2006. For dry goods and where sealing is not imperative, but the cost of the closure is, the cost of the material required for a full foil or even a donut foil is a significant factor. Usually, when a donut foil is used, a central part which is punched out to form the required shape, goes to waste. The need to reduce materials represents a technical problem.
Existing designs of childproof and tamper evident closures often require high tolerance to enable the parts to fit together properly. This makes them more expensive and requires the use of plastics materials which are capable of being moulded with greater precision. Low-cost blow moulded HDPE containers are therefore difficult to provide with childproof and tamper evident closures.
The present invention addresses the technical problems of providing a low-cost childproof and tamper evident closure that can also be used on containers manufactured to a low tolerance.